Obesity, polyps and a history of non-familial colorectal cancer appear to increase the risk of endometrial cancer in women with previous normal endometrial biopsy findings, a case-control study from the US has found.

Ninety women diagnosed with endometrial cancer between 1970 and 2008 were identified from the Rochester Epidemiology Project.

All had previously had a normal endometrial biopsy or D&C result.

The median time between biopsy and diagnosis of endometrial cancer was 6.7 years.

The majority of biopsies were done as part of the investigation of endometrial disease. Histological normality ranged between atrophic, secretory, proliferative and hyperplastic changes. Patients with atypical hyperplasia were excluded.

Demographics were compared with a matched control group of 172 women who had also had

a normal biopsy or D&C result. Three variables were associated with a significantly increased risk of endometrial cancer:

• BMI >35 kg/m2 odds ratio (OR) 3.4 (95% CI:1.18-9.78, P < 0.03),

• Polyps OR 4.12, (95% CI:1.4-12.17,

P = 0.01),

• Personal history of a non-familial colorectal cancer OR 4.44 (95% CI:1.02-19.31, P < 0.05).

Prior use of the combined oral contraceptive pill was found to be strongly protective against developing endometrial cancer,

OR 0.18 (95% CI:0.08-0.45, P < 0.001).

Compared with women without any of the above risk factors, the OR of developing cancer with one risk factor was 8.12 (95% CI:3.08-21.44, P < 0.001), and for women with two or more risk factors it was 17.87 (95% CI:5.57-57.39, P < 0.001).

Around one in forty women can expect to develop endometrial cancer during their lives, and the incidence of the condition is increasing.

It is thought that ever having had an endometrial biopsy is associated with an increased risk of endometrial cancer in the future. The authors suggest that following endometrial biopsy, any women with additional risk factors (obesity, endometrial polyps, prior colorectal cancer) should be considered at enhanced future risk.

Dr Chris Barclay

• Torres ML, Weaver AL, Kumar S et al. Risk factors for developing endometrial cancer after benign endometrial sampling. Obstet Gynecol 2012;120:998-1004